When is a well, not a well? When it's no well. Oh dear..... Mark tries to answer this question more thoroughly in Cumbernauld, and digs into the past of Scotland's famous New Town. Now infamous for its striking architecture, Mark looks back at the coining of the famous phrase "What's it called....Cumbernauld!" Going further back, he looks at what lies beneath some of today's surrounds- the old castle lying under and around Cumbernauld House- and tries to solve a listener's question about the presence, or not, of a motte and bailey castle. Produced by Lucy Adam.